1. Field of the Invention
This invention relates to an oil dispersant formulation and a process for dispersing spilled oil on water. More particularly, a formulation of chemical surfactants and inorganic salts results in a low toxicity dispersant which is effective at dispersing highly viscous oil at low concentrations in both salt and fresh water.
2. Description of the Related Art
One of the technologies used for oil spill response involves the use of chemical dispersants. The application of chemical dispersants is dependent on several factors: (1) weather conditions, (2) nature of the oil spilled, (3) area to be covered, (4) salinity of the water to be treated and (5) adequacy of equipment and supplies. Although it is highly desirable, it has not been possible to provide a single chemical dispersant formulation which will treat all oils under all conditions. For example, it is much more difficult to disperse a high-boiling viscous oil such a bunker oil as compared to a light crude oil. Furthermore, dispersant products which are effective in salt water often are substantially ineffective in fresh water.
A desirable property for chemical dispersants used to treat oil spills is that the surfactant formulation of the dispersant results in very low oil-water interfacial tension such that the oil is effectively dispersed as fine oil droplets in water without coalescing even at low dispersant to oil ratios. Also, the dispersant formulation should be of minimal toxicity so that it does not add to the environmental damage caused by the oil spill.
Various dispersant formulations have been advanced for treating oil spills. U.S. Pat. Nos. 5,618,468 and 5,728,320 disclose dispersant products which are highly effective for dispersing oil spills in salt water. In low salinity water, however, these dispersant products lose effectiveness and become ineffective in fresh water.